


Expanding the Greater Whole [CTF'd]

by CTFMeister



Category: Digimon Adventure Zero Two | Digimon Adventure 02
Genre: Cock Transformation, F/F, F/M, Futanari, Huge Dick, Light pain, Mental Transformation, Other, Pregnancy, Transformation, Twinning, huge insertion
Language: English
Status: Completed
Published: 2019-11-27
Updated: 2019-11-27
Packaged: 2021-02-26 04:48:06
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 4,576
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21587866
Author URL: https://archiveofourown.org/users/CTFMeister/pseuds/CTFMeister
Summary: "After Kari transforms into Tai's cock, an uninvited guest appears in the room: Kari's best friend Yolei. Tai tries to explain what happens, but as he gets up, he accidentally activates Kari's faulty digivice, causing him and Yolei to become much more like the digivice's owner."
Relationships: Inoue Miyako | Yolei Inoue/Yagami Taichi | Tai Kamiya, Yagami Hikari | Kari Kamiya/Yagami Taichi | Tai Kamiya
Kudos: 13





	Expanding the Greater Whole [CTF'd]

Little dew drops of cum dripped down from the ceiling onto the damp floor below, spluttering and splashing with tiny ‘plips!’ as they crashed against the jizz soaked wooden tiles. Lines of sperm dribbled down the walls, down the bedsheets, and down the shaft of Tai’s enormous penis as he sat on his bed, atop a puddle of his own spunk. Worse yet, besides having to deal with this disaster and needing to find a way to transform his sister back, it looked like he had also accidentally involved another unsuspecting party, for over in the other side of his room was his sister’s best friend, Yolei, standing there as if she’d seen a ghost with her clothes and glasses completely soaked in cum. This entire nightmare scenario had been his own creation. After giving in to his forbidden lust and fucking his sister, she had somehow transformed into his penis and caused the mess Tai stood before now.

Right by Tai’s door, Yolei slowly and calmly took off her glasses, her eyes squinting lightly as her vision momentarily got worse. She took the driest part of her sleeve and calmly wiped them off, acting as if nothing out of the ordinary was happening. Not because everything was as normal as it should be, but because she had no idea _how_ to act. How could she? After seeing her best friend’s brother masturbate a person sized dick and inundate his room with sperm, how was she supposed to act?

With her lenses cleared, Yolei placed her glasses back on her face. She looked deep into Tai’s eyes, her face morphing into a muddled expression of confusion, disgust and fear, as if she wasn’t sure whether she should ask Tai what was happening, yell at him for the strangeness of the situation, or run out of the room screaming. Tai could clearly see the turmoil going on in Yolei’s head with ease. He didn’t want her to panic- things were already as bad as is with Kari being transformed into his cock, he _really_ didn’t need to add further stress to it.

Summoning some of his remaining strength, Tai began to stand up from his bed. “Wait, Yolei!” He shouted, his arm reaching forward. “I can explain!”

When Tai’s foot reached the ground though, it did not find the flat firm squishy texture he was expecting. Rather, it was met with a squarish obtuse object, the whole cause for this mess in the first place, Kari’s malfunctioning digivice. Yes, as Tai attempted to stand up from his bed, he’d accidentally stepped on Kari’s faulty digivice instead of the floor. His foot ached with pain, the ridges of the device meshing against his foot. But more than just feeling a bit of pain, with his touch, Tai had accidentally caused the machine to turn on once again.

Soon the cracked screen began to light up, an eerie white glow crackling through its pixels and fractures. Digital information oozed from its insides, filling the real world with unknown unnatural energies. In response to its activation, the digivice scanned the genetic material of the one who’d initialized it, to make sure only its original owner was able to use it. And though it found traces of Kari in the organism that had turned it on, it also found a large amount of different genetic material sprouting about. To the the corrupted digivice, such a reading was absolutely unacceptable. Only Kari should be able to use it, not some strange Kari combination. So it did the only thing its glitched algorithms thought an appropriate response would be: To modify this organism genetic material to fit Kari more properly.

In less than a second, the digivice shot out a bolt of transformative data through this Tai’s body, filling him up with thousands of lines of his sister’s genetic material. Tai’s body began to spasm and twitch uncontrollably. It felt like lightning were coursing through his veins, as if he was being electrocuted whole. His legs and arms wailed wildly as more and more of his sister’s data was downloaded into his body. So much so that he’d accidentally lost his balance and tripped down onto the damp floor, flinging the digivice across the room.

Kari’s digivice slid through the damp sperm-ridden floor with ease, flying all the way towards the door unimpeded until it struck Yolei right in the foot. The girl didn’t have any time to process the pain of impact, for as soon as the Digivice touched her, it started to shoot the same transformative data it had been imparting on Tai onto her. Her body trembled furiously, low grunts and mumblings escaping her lips. The device did not realize it had been separated from its previous target, so it continued to operate as it did before, sending more of Kari’s genetic material via electric shock through Yolei’s body. Before long, the genetic transfer was complete, and Kari’s digivice became dormant once again. But the damage had been done. Kari’s digital genetic data flowed through Tai’s and Yolei’s bodies unimpeded, ready to make unwanted physical alterations to both of their bodies.

Tai slowly lifted himself up from the ground. His head buzzed with dizziness, a strange disorienting feeling dulling his senses. It felt like the whole world was going in slow motion, as if he’d been transported right into a bad dream. His insides gurgled loudly, skin stirring with uneasiness. The device had shocked him first, so his body would be the first to undergo wildly perverse changes. Starting off with his face, which shifted and turned bizarrely. The shape of his head became rounder and smoother. His eyelashes grew, eyebrows becoming thinner and nose becoming smaller. His rough boyish expression was replaced by a kind friendly look, as his face became much more feminine.

Next the top of his head began to rumble, his large triangular haircut shaking with fervor. The large frazzled hair on his head began to shrink down to his skull, while each of his locks took a lighter brown color. It became smaller and smaller, more compact and kempt, until his hairdo was silky, smooth and tidy. It still possessed a bit of its signature wildness, with a few hairs sticking out here and there. But overall, Tai’s hair had taken a more relaxed, friendly style, like that of his sister. 

Tai’s skin tingled, bubbling and shifting unnaturally. Starting from his face and going down through his body, soon his rough boyish skin was replaced with a softer daintier texture. Any sort of hairs that grew over his body, be it pubes or leg hairs or whatnot, receded back inwards, never to come out again. His body thinned out, any sort of muscle and strength transforming into untrained tissue. In a matter of seconds, Tai’s whole body had become soft and dainty, like that of a prim and pretty young woman.

The strange warmth then moved on to a different part of his body, focusing entirely on his chest. A small shock of electricity coursed through his nipples, making Tai give out a little moan. His nipples slowly became erect, areolas increasing in size. Tai’s chest throbbed lightly, as if it was filling with warmth. Because unbeknownst to him, his chest was actually filling up with more mass. While Tai remained in his ethereal distracted state, his chest slowly bloomed into two round breasts. They didn’t grow too large, only into B-Cups, appropriate for a girl Tai’s age. But they stood out proudly nevertheless, obvious protrusions that would not normally be on a boy like Tai.

Still, this change was nothing for what was about to happen to Tai. With his entire body properly feminized, the code running within Tai’s blood focused on a specific area: His taint. Right between Tai’s plump ballsack and his tight anus, a strange prickling feeling began to form. It ached lightly, as if a hole was being pushed right into his body. Because in a way, it was. Without any warning, a small vertical slit was forming behind Tai’s balls. The brand-new hole snaked inwards, pushing away vital organs and creating a brand new organ, an organ that exuded pure feminine energy, an organ that should only be found in a dainty girl’s body, a fully functioning uterus.

As soon as Tai’s transformation concluded, Yolei’s changes began to pick up. The girl staggered forward clumsily, the strange sensations muddling her mind past comprehension. It felt like her body was being bombarded with heat, little bursts of warmth exploding all over her body. The aching was so bad that Yolei couldn’t contain herself anymore. Her hands instinctively reached towards her clothes, tugging them off with reckless abandon. It didn’t matter that Tai was here, or that something was clearly wrong in this place. She just needed to get her clothes off! Her vest was easy to remove. Her dress took a bit more effort, given that it only had a few places she could take it off through. Even her headpiece fell as she slid the her dress off through her head. In a matter of seconds, Yolei was fully nude save for her underwear.

Not that this would prevent her metamorphosis. Soon, her hair was already beginning to change. First her long flowing locks slowly retreated back into her head, all their luster and splendor sinking back into her skin. Then, streaks of brown began to color each strand of hair. Though it was miniscule at the start, only being visible on her hair ends. As the hair continued to shrink, the color spread on father, until the lower half of her hair was full on brown while the rest remained its original magenta. In a few moments, Yolei’s hair finished to accommodate itself into a more reserved and orderly hairstyle. The influence of Kari’s genetic data was becoming clearer and clearer.

Next came Yolei’s body. The extra feminine data caused Yolei’s body to blossom further. Her breasts blew out, from totally flat into nice A-cups. Her hips expanded, butt growing larger and body growing curvier. Since they were both girls, Yolei’s body didn’t change much more than that. Instead, what _really_ changed was Yolei’s demeanor. Her posture shifted, from confident and tomboyish, to gentle and demure. Her fiery expression transformed into one of cheerful joy. Any type of boyish behavior gained a tinge of feminine graces. Now when one looked at Yolei, they would no longer see the energetic tomboy she used to be. They would find a new soft and sweet dimension, like that of her previous best friend.

Soon, both Tai and Yolei had completely transformed. Kari’s genetic material had been equally distributed throughout their bodies, so that each was half Kari, half themselves. However, though the physical changes were over, that did not mean their strange journey was at an end. Both of their minds continued to be plagued by an odd heat, a muddling warmth that fogged up their brains. Not a thought passed through, not an idea could be thought, their brains had been turned into complete and utter mush.

That is when Tai lifted up his gaze. His eyes laid onto Yolei’s fantastical nude form. In turn, Yolei looked at Tai, her eyes focusing on his gigantic cock. Their visions slowly met. Gazes interlocking togethers, a spark lit up in both of their eyes as their minds glowed in recognition. In that single second, all the fog was lifted up from their brains. Finally, the two understood what the strange sensations which wracked their bodies were. It was lust. Tai and Yolei’s bodies were brimming with lust. A deep desire that was finally unleashed once they laid eyes on each other. When Tai looked at Kari’s half within Yolei, he was instantly enraptured. Inversely, when Yolei’s Kari half looked at Tai, she was fully entranced too. It only took one moment, but with both of their libidos enflamed, their fates had been set.

Body propelled by nothing but pure desire, Yolei trudged forward through the swampy cum-soaked floor. She stepped closer and closer to Tai, drifting left and right like a zombie as she pursued her deep burning lust. Eyes glazed, thoughts muddled, her pussy quivered with need at the mere sight of Tai’s cock. Meanwhile, Tai couldn’t even budge an inch as he stared at Yolei’s magnificent body. He was so aroused, all other body functions had been frozen in favor of lusting over this pristine beauty. What he saw in Yolei was truly amazing. It was as if his sister had been transported back into his room and was ready to have intercourse with him once more. Kari slowly began to grow erect, her brother’s feeling flowing through her veins. Though she could not see what was happening, she was nonetheless excited to feel arousal from him once more.

The moment Yolei arrived next to Tai, she sunk to her knees, cum splashing away from her legs. The two aroused people stared into each other’s eyes, their lust fully palpable. They didn’t have to exchange another word. Both knew exactly what they wanted. Without any delay, Tai and Yolei lunged towards each other, their lips interlocking together as they melded into a passionate kiss. Saliva flew freely from one mouth to another, tongues mashing against each other lovingly. Though neither had really felt strong feelings of affection towards each other before, now they were truly and completely in love, as if they’d been dating their entire lives.

A burst of arousal awakened Kari to a fuller excited state. She could feel it-! Tai’s lips were smacking against another set of soft voluptuous lips. There was another girl! Tai was about to have sexual intercourse with another girl, and Kari could finally be useful to him! Blood and excitement flowed through Kari’s veins, her body growing larger and thicker. Her bulbous dickhead poked out through Tai’s foreskin, glowing a proud vibrant red. Her length twitched left and right, as her body grew stiffer and her veins became more prominent. Even her balls plumped up, growing fuller and rounder with thousands and millions of eager sperm. Tai felt a little lightheaded with so much blood flowing into his penis. Nonetheless, his arousal was titanic, and soon his Kari-dick was the same monstrous size it was before, taller and thicker than Tai himself.

With Kari growing larger and larger, soon Yolei’s kiss with Tai kiss was broken apart by his massive length. Yolei staggered back, pushed away by Tai’s extreme girth. Her eyes focused on his titanic cock, mouth opening in surprise. It was so amazingly large~ Yolei could barely believe that her brother- er, her best friend’s brother would posses such a tool. Her organ screamed with lust, vaginal juices squirming out of her hole. She wanted it so badly~ Unable to hold herself back, Yolei laid down on the floor, not caring one bit as the whole back of her body and even hair was soaked in sperm. She took her hands and spread her pussy as far as she could. She couldn’t wait to take Tai’s manhood~

Heavy breaths escaped Tai’s lips. Most of the blood that circulated into his brain was going to his huge cock, leaving his absolute lust as the only source of mental stimulation. Hungry for sex, he stumbled closer to Yolei, his steps awkward because of how tremendously large his assets were. Kari twitched with excitement, feeling Tai just a few meters away from his eager lady. Tai dropped his cock on top of Yolei, hitting her square in the face with a thick slab of dick meat. Though Yolei didn’t complain. With her lust levels as elevated as his, she reached her arms out and hugged the huge member, forcefully licking and groping it.

Yolei’s bodyjob was truly marvelous, but Tai was hungry for something different. He slowly pulled back, sliding Kari from the top of Yolei’s body down to her lower side, right between Yolei’s legs. His cock meshed against his damp seed on the floor, its whole underside being covered in white. By this point, it was growing cold, but it didn’t faze Tai in the slightest. All the warmth he needed was right in his enormous sister-dick. Tai pushed forward, the tip of his dick pressing against Yolei’s labia. Kari twitched happily. She could feel the pussy right there! The excitement of being a good dick and bringing pleasure to her brother burned with so much ardor within her, she pushed onwards without her brother’s permission. Not that Tai was resisting, for his own body pressed forward fueled by lust. Yolei, meanwhile, gave an uncomfortable grunt. As Tai continued to his cock against her organ, she felt how the girth of Tai’s dickhead was as big as her body. A twinge of doubt seeped into her mind. Maybe… Maybe this wasn’t such a good idea.

But it was too late. With one powerful thrust of his hips, Tai pushed Kari forward, shoving her entire head into Yolei’s vaginal canal. Eyes shooting wide open, Yolei screamed as loud as her vocal cords allowed her. Inch by inch, more of Kari’s dickhead sunk into her womanhood, prying Yolei’s vaginal walls open by force until the entire dick head had been fully swallowed, from its tip down to its plump outer rim. Yolei’s body was entirely in shock. It felt like her entire body was being ripped into two, her legs stretching outwards in opposite directions. To say there was pain was an understatement. Yolei’s lower body ached with such fervor, it was actually going numb. The top of Tai’s dick bulged through Yolei’s crotch, showing his mushroom-like tip etched on her skin in vivid detail. And that was just the beginning. Not even one quarter of Tai’s dick had even been inserted into Yolei and the girl was writhing on the ground in pain.

Meanwhile, Tai and his penis were having the complete opposite experience. Face colored with pure joy, Tai basked in the deliciousness of Yolei’s pussy. Sure, it was tight, but it never felt constricting. The way her vaginal walls wrapped around his tip was amazing, like a finely refined sexual toy. Similarly, Kari was also enjoying the experiences of being a dick. Her whole shaft throbbed with delight, feeling the way her head was consumed by Yolei’s fleshy inner wall. The only downside was this immaculate pleasure was that it was only afflicting his tip, and not his whole body. Tai and his penis tried to press onward, but Yolei’s insides were tightly shut, attempting their best to prevent further invasion. Though it was ridiculous to think this would stop Tai. His arousal was so immense at this moment, he was ready to push as hard as he needed to.

Her shaft body throbbing, Kari continued to drill through Yolei’s organ. The bulge on Yolei’s crotch slowly grew larger and larger, her soft skin being no match to the power of Tai’s monster cock. She was being rocked with so much intensity, Yolei was about ready to pass out. Tai’s cock- Her dearest Tai’s cock, it was just way too big for her. Even though she really wanted him to fuck her, though she wanted to make him happy… Fueled by this intense pain, Yolei’s mind entered a moment of delirium. Without any warning, Kari’s desires took over Yolei’s body. And soon after, all pain instantly seized from her organ. Though her body was being stretched past what should be humanly possible, just the fact that she was having sex with Tai was filling her with pleasure. Yolei’s insides softened, her organ coursing with more lubrication. She was… She was really starting to enjoy Tai’s cock!

With a change in Yolei’s attitude, Tai’s whole expedition into her pussy changed. Yolei’s vaginal walls softened, birth canal opening for Tai to further explore. She was letting him in! An opportunity both Tai and Kari were eager to explore, as they pressed deeper and deeper into Yolei’s vagina. More and more, the bulge on Yolei’s crotch grew in size, into a formidable dick shaped bump. The two only stopped once they reached the entrance to Yolei’s womb. And were it not for the fact that Kari’s peeslit was larger than the entrance to Yolei’s womb itself, the two would have pressed on farther. Still, Kari did not feel deterred. Tai pushed and pushed his dick deeper inside, until he could physically push no further. Though he had only been able to shove half of his mast into Yolei’s delectable pussy, the pleasure he felt squeezing his length more than made up for it.

Throughout it all, Yolei no longer felt any pain. On her face a dull blissful expression was permanently plastered. Even as Tai began to slowly fuck her mound, shuffling his dick back and forth in her hole, Yolei could not think of any discomfort. Her mind was completely overtaken by images of Tai and his delicious gigantic cock. Tai~ The sweet beautiful Tai~ Yolei had never thought very much of him before, but now she couldn’t get him off her mind. She loved him so much, every inch of him. From his cute face, to his pretty breasts, to his succulent form. Their bond was so tight, it was like they were brothers. Yolei’s body trembled pleasurably at the thought. Yes… That sounded so right~ Yolei and Tai were like brothers~ Like siblings~ Like… Sisters~~ Yolei’s eyes shot backwards, her tongue lolling out of her mouth. Her brain was being rewired as Tai continued to penetrate her.

Hands on his shaft, hips moving groggily, Tai did his best to fuck Yolei’s pussy with all his might. His eyes settled on Yolei’s beautiful form. Her petite frame, her short brownish hair… It reminded him of his sister… Oh his sweet sister, whom he loved so fervently… If only he could fuck her pussy again. If only… Yolei was her sister~? Tai’s hips began to pick up speed, his thrust growing with power. The thought thoroughly aroused him. He really wanted to be with his sister. And Yolei looked like his sister. So maybe… Maybe Yolei _should_ be his sister. Kari twitched in response, stimulus shooting through her body. Yes, that was absolutely wonderful. Tai… He- He-! … _She_ needed to be with her twin sister again~

Yolei’s and Tai’s eyes met each other’s gazes, a spark of lust lighting up in their pupils. A new set of memories flashed before their eyes, as their entire identities shifted. They were no longer Tai and Yolei, mere acquaintances. They were Tari and Kalei, twin sisters and _lovers~_ A smile of pure joy crossed upon both of their faces. Though they could remember their previous realities, though they could understand these new memories were being forcibly planted, the two sisters happily embraced their new selves. Tari thrust her dick with even more fervor, the sperm in her sack churning and ready for release. Kalei too matched her sister’s movements, pussy quivering in need of orgasm. No longer did they have any doubts or apprehensions, their minds and bodies had been united in ecstasy.

“SIS, I’M GONNA CUMMM~~~” Tari screamed out pleasurably.

“FILL ME UP SISSSSS!!!” Kalei shouted back.

A blast of pleasure shot through Kari’s mind, her dicklips twitching before they released a flood of sperm directly into Kalei’s vagina. Cum shot out of Tari’s dick like water out of a firehose. It spurted and spurted with force, piercing into Kalei’s womb and coloring every inch of her vagina in goopy white. Soon, a large circular bulge began to grow on Kalei’s stomach. Her uterus was slowly being inflated with sperm, growing larger and larger with no signs of stopping in sight. From the size of a tennis ball, up to a basketball, and then larger than a melon, as Tari continued to cum, Kalei’s belly continued to bloat, way past what should be humanly possible. It got so big in fact, it started to look like she was pregnant with multiple children.

Eventually, this thick powerful flow stopped, though not because of a lack of sperm. No, Kari was good to release a few more solid gallons. The problem was that she felt a tingling course up through her urethra. Not sperm, but something much different, like a part of her essence was expelled. This tingling sensation flowed all the way to the tip of Kari’s head. Compressing her dick-muscles, she did her best to push it out, squeeze it so she could release more sperm. Kari squeezed and squeezed until-

**_POP!!!_ **

Her essence finally blasted out of her slit, shooting right into Kalei’s uterus and resuming the torrent of seed. This explosion was so hard that it sent Tari flying backward, making Kari pop out of Yolei’s widened pussy and into the open air. Even then though, Tari did not stop expelling cum. As Tari fell on her butt, Kari twitched up and down madly, spraying lines of jizz on herself, her room and Kalei. The two sisters groaned in glee as seed rained down on top of them, their orgasms having brought them such ethereal joy, not one single more care could enter their hearts.

Unbeknownst to either of them though, one final change was progressing within Kalei’s body. Despite lacking physical form, a part of Kari’s essence did in fact enter into Kalei’s womb, resting within her center. It was the shape of a small sphere, a ball of empty air and human soul resting within Kalei’s uterus. The sperm around Kari’s essence began to swirl around the orb. From left to right, up and down, it surrounded the sphere whole, coagulating into something entirely new. Revolution after revolution, the sperm transformed, from solid to liquid, from sperm into tissue. Within a few seconds of solidifying, the sperm around Kari’s essence had developed into a heart, fully functional and beating.

Soon, more organs formed around it, each growing stronger and firmer by the second. Though they had been made of sperm, once fully constructed, they were no differences between that of any normal person. A full body of meat encased the organs, filled with bloods, vessels and veins. Limbs began to form, two long arms and legs, and a head was constructed, taking a lot of information from the essence to form the brain. Two budding breasts developed in this creature’s chest, brown hair sprouted from its cranium, and a cute sisterly face formed on its head. Its features were unmistakable, its identity absolutely clear. With an umbilical chord reaching deep into this girl’s belly button, it was easy for any to see: An exact replica of Kari, the same age as she was before her merging, had formed deep within Kalei’s body, a child of the two new sisters.

As for when she would be born and how the birth would go, only time would tell. But for now, lacking any knowledge of the developments within Kalei’s uterus, the two sisters happily wallowed in the sea of cum that covered the room’s floor. Kalei slowly looked over at her sister Tari, her big stomach making movement extremely difficult, and Tari lovingly looked back. A smile of pure bliss covered each of their faces.

“You think we should invite TK and Davis?” She asked her sister lustfully.

The eager smile on Tari’s face was all the response she needed. “Of course~”

**Author's Note:**

> Whoooop! This is done. This is the first story of the month I think, which is pretty wacky, cus I have a TON more to get through and its already like halfway through. *Sigh* I'm doing my best here guys! Next week there'll definitely be another fic. Maybe if I'm lucky I can get two fics in one week, but the next two are 4k ones, so we'll just have to wait and see. Anyways, this is a sequel to that other Digimon story I did. Hopefully it ends up well, since I don't know much about the characters. But regardless, I hope you enjoyed this one and cheers!


End file.
